1.67 ×21 +18 ×21 + 85 ×79
2. 375 ×480 + 6250 ×48
3. 321 ×81 + 321 ×19
4. 222222 ×999999
5. 333333 ×333333
6. 654321 ×909090 +654321 ×90909
7. 34 ×3535 -35 ×3434
8. 345345 ÷15015
9. 75 ×45 + 17 ×25
10. (48 ×75 ×81)÷(24 ×25 ×27)
【答案详解】
1. 67 ×21 +18 ×21 + 85 ×79 =21×(67+18)+85×79 =21×85+85×79 =85×(21+79) =85×100 =8500
2. 375 ×480 + 6250 ×48 =480×(375+625) =480×1000 =480000
3. 321 ×81 + 321 ×19 =321×(81+19) =321×100 =32100
4. 222222 ×999999 =222222×(1000000-1) =222222×1000000-222222×1 =222222000000-222222 =222221777778
5. 333333 ×333333 =111111×999999 =111111×(1000000-1)
=111111×1000000-111111×1 =111111000000-111111 =111110888889
6. 654321 ×909090 +654321×90909 =654321×(909090+90909) =654321×999999 =654321×(1000000-1) =654321×1000000-654321×1 =654321000000-654321 =654320345679
7. 34 ×3535 -35 ×3434 =34×35×101-35×34×101 =0
8. 345345 ÷15015 =345×1001÷(15×1001) =345÷15×1001÷1001 =23
9. 75 ×45 + 17 ×25 =25×3×45+17×25 =25×(135+17) =25×152 =25×4×38 =3800
10. (48 ×75 ×81)÷(24 ×25 ×27) =(48÷24)×75÷25×81÷27 =2×3×3 =18
希望能帮到你,望采纳,谢谢!